The tonfa is a simple wooden bludgeoning weapon used in kobudo. It consists of a wooden stick with a handing protruding from the side about two thirds of the way down the length of it. This is very similar to the baton seen in popular media being used by law enforcement except that tonfa are used in pairs.
Holding the longer side of the tonfa along the forearm allows the karate-ka to block attacks that would otherwise damage their arms, such as attacks with weapons. The same techniques used in Shorin-Ryu will work if adapted to the tonfa.